Historically, tissue has been cut with scissors of various designs by a mechanical shearing action as sharpened blades move past each other on closing. The mechanical limitations of typical scissor designs and the variation in tissue types result in the following problems and complications: tissue squeezing out of the scissor on compression (“popping out”); incomplete cuts; cut edges that are uneven (caused by dull scissors or changes in tissue type); the inability to see/determine exactly what is being cut; separation and jamming of scissor blades without cutting tissue when fibrous, fatty, or tough tissue gets caught between blades; and dulling of the scissors due to limitations of materials and mechanisms. Additionally, the sharp blades of traditional scissors may inadvertently knick or damage other tissues or structures, such as nerves, blood vessels, tendons, sutures, implanted electrical leads (pacemaker, defibrillator, neural stim, etc.) and surgical personnel. Furthermore, general scissor designs do not provide a mechanism to stop bleeding once tissue has been cut.
With the advent of electrosurgery, both monopolar and bipolar scissor designs have been produced to allow for application of electrical energy to stop bleeding after tissue has been cut with the scissors. These designs have attempted to combine both the mechanical shearing action of a regular scissor and the application functionality of electrosurgical energy in both cut and coagulation modes. However, attempts to concentrate electrical energy in a focused manner to enhance the cutting effect have been sparse. Indeed, most efforts have been with bipolar instruments which typically attempt to achieve a small activation zone effect through optimal electrode distances and placement.